1. Field of the Invention
The present invention relates to antennas, more particularly to integrated antennas for portable computers.
2. Description of the Related Art
Typically, a wired cable is used by a laptop to communicate with another processing device such as another laptop, desktop, server, or printer. To communicate without a wired connection, an antenna is needed. FIG. 1 shows a laptop with external antennas. Antenna 10 is located at the top of a laptop display for better RF clearance, or just outside (dash line for antenna) of a PCMCIA card 11. Usually, optimum wireless performance is achieved if the antenna is mounted on the top of the display 10. As compared to internal antennas, external antennas are generally more expensive and are more susceptible to damage.
An internal or embedded antenna generally will not perform as well as an external antenna. The commonly used method to improve the performance of an embedded antenna is to keep the antenna away from any metal component of the laptop. Depending on the design of the laptop and the type of antenna, the distance between the antenna and metal components should be at least 10 mm. FIG. 2 shows prior art embedded antenna implementations in which two antennas are typically used. Two whip-like/slot embedded antennas are placed on the left 20 and right 21 edge of the display. Using two antennas instead of one antenna will reduce the blockage caused by the display in some directions and provide space diversity to the communication system. As a result, the size of the laptop becomes larger to accommodate antenna placement. In another configuration, one antenna can be placed on one side (20 or 21) of the display and a second antenna on the top 22 of the display. This latter antenna configuration may also provide antenna polarization diversity depending on the antenna design used.
As wireless communications among processing devices become increasingly popular, a need exists for a compact integrated antenna having reduced costs and enhanced performance.
An antenna for integration into a portable processing device having a display is provided. According to an aspect of the present invention, the antenna comprises: a metal frame embedded in a housing of the display; a radiating element extending from the housing; and a conductor having a first component for carrying a signal to the processing device and a second component for connecting to the metal frame for grounding the radiating element. The conductor is preferably a coaxial cable having an inner feed conductor connected to the radiating element and an outer conductor connected to the metal frame.
The radiating element may be one of an inverted-F antenna and a slot antenna.
The antenna according to an illustrative embodiment further includes a feed conductor for impedance match, the feed conductor being disposed at about midpoint of the length of the antenna arrangement. The radiating element may be disposed substantially along a x-y plane of the display, or disposed substantially transversely to the x-y plane of the display.
According to another aspect of the invention is an antenna arrangement comprising: a conductive RF shielding foil disposed on the back of an electronic display the foil having an opening; and a slot antenna having a feed portion extending partially through the opening of the foil. Preferably, the antenna arrangement further comprises a conductor comprising a first component for conducting the signal connected to the feed portion and a second component for grounding the conductor connected to the RF foil opposite the feed portion.
An integrated antenna arrangement according to another embodiment of the present invention comprises: a conductive RF shielding foil disposed on the back of an electronic display having a notch; and a feed portion extending partially across the notch forming an inverted-F antenna. The antenna further comprising means for conducting a signal comprising a first component for conducting the signal connected to the feed portion and a second component for grounding the conducting means connected to the RF foil opposite the feed portion. The means for conducting the signal is preferably a coaxial cable having an inner conductor connected to the feed portion and an outer conductor connected to the RF foil opposite the feed portion.
An antenna according to still another embodiment of the present invention is integrated in a portable computer having a display, comprising: a metal support embedded in a housing for supporting the display; a radiating element extending from the metal support; a first conductor for carrying a signal from a first portion of the radiating element to the computer; and a second conductor for connecting a second portion of the radiating element to the metal support for grounding the radiating element.